The present invention relates broadly to a heat exchanger of the type having a tube provided with a passage or passages through which a heat-exchange medium is circulated and a multiplicity of fin assemblies each having a large number of fins and attached to the tube so that a heat exchange is performed between the heat-exchange medium flowing in the tube and a gas flowing through the space between adjacent fins of each fin assembly. More particularly, the present invention is concerned with an improvement in the fin assembly for use in the heat exchanger of the type described.
Japanese Patent Publication No. 27263/1973 discloses a heat exchanger of the kind mentioned above, in which the fins of the fin assembly are inclined with respect to the direction of flow of the gas, and each fin has a plurality of louvers cut out and protruded from the major plane of the fin. These louvers are arranged in parallel with the direction of flow of the gas. In this known heat exchanger, it is intended, by inclining the fins, for the gas to be positively introduced and to flow through the gap between adjacent louvers, when the gas flows through the space between the fins, thereby increasing the heat transfer coefficient. However, since the louvers are arranged in parallel with the direction of flow of the gas, the gas does not flow through the gap between louvers in such a manner as to increase the heat transfer coefficient to a satisfactorily high level when the inclination of fins is small.